Aliphatic polycarbonate macropolyol and aliphatic polycarbonate-coaromatic polyester macropolyol

ABSTRACT

Provided is an aliphatic polycarbonate macropolyol including —OAO— and Z(O—) a  as repeating units. In the aliphatic polycarbonate macropolyol, the repeating units —OAO— and Z(O—) a  are linked to each other via carbonyl (—C(O)—) linkers or are bonded to hydrogen to form terminal —OH groups. The number of moles of the terminal —OH groups is from aZ to aZ+0.2Z (where Z represents the number of moles of the repeating unit Z(O—) a ). Further provided is an aliphatic polycarbonate-co-aromatic polyester macropolyol including —OAO— and Z(O—) a  as repeating units. In the aliphatic polycarbonate-co-aromatic polyester macropolyol, the repeating units —OAO— and Z(O—) a  are linked via carbonyl (—C(O)—) and —C(O)YC(O)— as linkers or are bonded to hydrogen to form terminal —OH groups.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Division of application Ser. No. 14/909,568 filedon Feb. 2, 2016 now abandoned which in turn claims the benefit ofInternational Application No. PCT/KR2013/009222 filed on Oct. 16, 2013,which in turn claims the benefit of Korean Patent Application No.10-2013-0096100 filed on Aug. 13, 2013, the disclosures of which areincorporated by reference into the present application.

TECHNICAL FIELD

The present invention relates to an aliphatic polycarbonate macropolyol,an aliphatic polycarbonate-co-aromatic polyester macropolyol, andmethods for producing the macropolyols. More specifically, the presentinvention relates to an aliphatic polycarbonate-co-aromatic polyestermacropolyol that can be utilized as a polyurethane raw material, acoating material, a lubricating agent, etc., and a method for producingthe macropolyol.

BACKGROUND ART

Aliphatic polycarbonates are biodegradable eco-friendly polymers. Themost suitable process for the mass production of aliphaticpolycarbonates is the condensation of dimethyl carbonate (DMC) withdiols. DMC have been produced from toxic phosgene. Efforts have beenmade to develop processes for the production of DMC using carbonmonoxide or more environmentally friendly carbon dioxide instead ofphosgene. The use of carbon monoxide or carbon dioxide enables theproduction of DMC on a large scale at low cost. There are many reportsin the literature on the condensation reactions of DMC and diols.However, the condensation reactions are slow and have limitations inobtaining high-molecular-weight polymers. Under these circumstances,oligomeric macrodiols having molecular weights on the order of severalthousands and terminal —OH groups are currently produced and only smallamounts thereof are used as polyurethane raw materials.

Approximately 10 million tons of polyurethane is produced globally everyyear. Polyurethane can find application in thermoplastic plastics,thermosetting plastics, elastomers, and the like. Most macropolyolshaving terminal —OH groups for polyurethane production arepolyether-based compounds obtained via ring-opening polymerization ofethylene oxide or propylene oxide. Some aliphatic polyester-diols and-polyols are also used for polyurethane production. Aliphaticpolycarbonate-diols and -polyols are used in relatively very smallamounts but are known to have good hydrolysis resistance and be highlyresistant to degradation by light and oxygen (EP 302712).

DETAILED DESCRIPTION OF THE INVENTION Problems to be Solved by theInvention

An object of the present invention is to provide an aliphaticpolycarbonate macropolyol, an aliphatic polycarbonate-co-aromaticpolyester macropolyol, and methods for producing the macropolyols.

One aspect of the present invention provides an aliphatic polycarbonatemacropolyol including —OAO— and Z(O—)_(a) as repeating units in whichthe repeating units —OAO— and Z(O—)_(a) are linked to each other viacarbonyl (—C(O)—) linkers or are bonded to hydrogen to form terminal —OHgroups and the number of moles of the terminal —OH groups is from aZ toaZ+0.2Z (where Z represents the number of moles of the repeating unitZ(O—)_(a)) wherein A is a substituted or unsubstituted C₃-C₆₀ alkyleneor a combination of two or more substituted or unsubstituted C₃-C₆₀alkylenes, a is an integer from 2 to 4, provided that when a is 2, Z isa substituted or unsubstituted C₃-C₆₀ alkanediyl, when a is 3, Z is asubstituted or unsubstituted C₃-C₆₀ alkanetriyl, and when a is 4, Z is asubstituted or unsubstituted C₄-C₆₀ alkanetetriyl.

As used herein, the term “macrodiol” refers to a linear polymer whoseends are all capped with —OH and whose degree of polymerization is from5 to 25. The term “macropolyol” refers to include the macrodiol and abranched polymer whose ends are all capped with —OH and whose degree ofpolymerization is from 5 to 25. Therefore, unless otherwise mentioned,the term “macropolyol” is intended to include the macrodiol.

The term “alkyl” used herein is intended to include straight chained,branched, and cyclic hydrocarbon radicals. The term “alkylene” refers toa divalent radical derived from alkyl. For example, the alkyleneincludes methylene, ethylene, isobutylene, cyclohexylene,cyclopentylethylene, 2-prophenylene, and 3-butynylene. The main chain ofthe alkylene may be interrupted by —O— or phenylene. The term“substituted” in the expression of “substituted or unsubstituted”described herein means that one or more hydrogen atoms in thehydrocarbon are each independently replaced by the same or differentsubstituents. Suitable substituents include, but are not limited to,—R^(a), -halo, —O⁻, ═O, —OR^(b), —SR^(b), —S⁻, ═S, —NR^(c)R^(c),═NR^(b), ═N—OR^(b), trihalomethyl, —CF₃, —CN, —OCN, —SCN, —NO, —NO₂,═N₂, —N₃, —S(O)₂R^(b), —S(O)₂NR^(b), —S(O)₂O⁻, —S(O)₂OR^(b),—OS(O)₂R^(b), —OS(O)₂O⁻, —OS(O)₂OR^(b), —P(O)(O⁻)₂, —P(O)(OR^(b))(O⁻),—P(O)(OR^(b))(OR^(b)), —C(O)R^(b), —C(S)R^(b), —C(NR^(b))R^(b), —C(O)O⁻,—C(O)OR^(b), —C(S)OR^(b), —C(O)NR^(c)R^(c), —C(NR^(b))NR^(c)R^(c),—OC(O)R^(b), —OC(S)R^(b), —OC(O)O⁻, —OC(O)OR^(b), —OC(S)OR^(b),—NR^(b)C(O)R^(b), —NR^(b)C(S)R^(b), —NR^(b)C(O)O⁻, —NR^(b)C(O)OR^(b),—NR^(b)C(S)OR^(b), —NR^(b)C(O)NR^(c)R^(c), —NR^(b)C(NR^(b))R^(b), and—NR^(b)C(NR^(b))NR^(c)R^(c), where R^(a) is selected from the groupconsisting of alkyl, cycloalkyl, heteroalkyl, cycloheteroalkyl, aryl,arylalkyl, heteroaryl, and heteroarylalkyl groups; each R^(b) isindependently hydrogen or R^(a); each R^(c) is independently R^(b), withthe proviso that the two R^(c) groups, together with the nitrogen atomto which they are attached, may form a 4-, 5-, 6- or 7-memberedcycloheteroalkyl and may optionally include 1 to 4 identical ordifferent additional heteroatoms selected from the group consisting ofO, N, and S. As a specific example, —NR^(c)R^(c) is meant to include—NH₂, —NH-alkyl, N-pyrrolidinyl, and N-morpholinyl. As another example,the substituted alkyl is meant to include -alkylene-O-alkyl,-alkylene-heteroaryl, -alkylene-cycloheteroalkyl, -alkylene-C(O)OR^(b),-alkylene-C(O)NR^(b)R^(b), and —CH₂—CH₂—C(O)—CH₃. The one or moresubstituents, together with the atoms to which they are attached, mayoptionally form cyclic rings including cycloalkyl and cycloheteroalkyl.

FIG. 1 compares a conventional method for producing an aliphaticpolycarbonate macrodiol with a method for producing an aliphaticpolycarbonate macrodiol according to the present invention. According tothe method of the present invention, an aliphatic polycarbonatemacropolyol is produced by condensing HOAOH as a diol with DMC in thepresence of a base catalyst while removing methanol to prepare analiphatic polycarbonate with a number average molecular weight of 10000or higher (first step) and transesterifying the high-molecular-weightcondensation product with a diol, triol or tetraol compound Z(OH)_(a)(where a is an integer from 2 to 4) (second step). In the second step,the transesterification occurs in the presence of the catalyst used inthe first step according to the mechanism depicted in Reaction Scheme 1and proceeds rapidly at a condensation temperature of 180 to 190° C. toreach equilibrium in a few hours. The equilibrium indicates that therepeating units —OAO— and Z(O—)_(a) shown in Reaction Scheme 1 arerandomly distributed in or between the polymer chains.

FIG. 2 shows the distribution of the chains of the macrodiol in whichthe repeating units —OAO— and Z(O—)₂ are randomly distributed, aftertransesterification with the diol compound Z(OH)₂ as a chopping materialin the second step. The degree of polymerization (DP) of the finalmacrodiol is calculated by dividing the total number of moles N+Z of therepeating units —OAO— and Z(O—)₂ by the sum of the number of moles ofthe polymer chains formed in the first step and the number of moles Z ofthe diol compound Z(OH)₂ added in the second step. When the polymerprepared in the first step has a sufficiently high molecular weight, thenumber of moles N/n of the polymer chains formed in the first step isinsignificant and negligible compared to the number of moles Z of thediol compound Z(OH)₂ added in the second step, and as a result, the DPcan be defined as (N+Z)/Z. From a statistical viewpoint, the probabilityf_(k) of the number of chains including kZ(O—)₂ repeating units isrepresented by _(a)C_(k)(1−1/a)^(a-k)(1/a)^(k) when the DP is expressedas a natural number a close to (N+Z)/Z. For example, the f_(k) values ofmacrodiols produced in Examples 1-9 can be calculated as follows.High-molecular-weight aliphatic polycarbonates were prepared in yieldsof about 90% from 111 mmol of HOAOH. Thus, N is about 100. 16.7 mmol ofZ(OH)₂ was added as a chopping agent in the second step. Thus, DP (i.e.a) is calculated to be about 7 ((100+16.7)/16.7). In this case, theprobability f₀ of the number of chains having none of the Z(O—)₂ units,the probability f₁ of the number of chains having one Z(O—)₂ unit, theprobability f₂ of the number of chains having two Z(O—)₂ units, theprobability f₃ of the number of chains having three Z(O—)₂ units, andthe probability f₄ of the number of chains having four Z(O—)₂ units arecalculated to be 35%, 40%, 19%, 5.3%, and 0.9%, respectively. Fromanother viewpoint, the total number of moles of —OH groups is maintainedunchanged during chopping. That is, the total number of moles of —OHgroups in the Z(OH)₂ initially added in the second step is the same asthe number of —OH groups in the final macrodiol (that is, Σx_(k)=Z). Thenumber of moles of the Z(OH)₂ added should be identical to that of theZ(O—)₂ units included in the final macrodiol (that is, Σk·x_(k)=Z). Fromboth equations, f₀=f₂+2f₃+3f₀₄+ . . . is derived. This equation issatisfied when the f_(k) values obtained in Examples 1-9 are substitutedthereinto.

In the second step, Z(OH)₃ as a triol compound may be added as achopping agent for transesterification. As a result of the reaction, amacropolyol is obtained in which the repeating units —OAO— and Z(O—)₃are randomly distributed in or between the polymer chains. Thestatistical distribution of the chains of the macropolyol can also beinferred in the same manner as in the macrodiol (FIG. 3).

The present invention is based on a technique for producing ahigh-molecular-weight aliphatic polycarbonate in the presence of a basecatalyst. The development of efficient techniques for producingaliphatic polycarbonates with molecular weights on the order of severaltens of thousands is still in an early stage. The equations shown inFIGS. 2 and 3 are under the assumption that the DP of the polymerprepared in the first step is very high and the number of moles of thepolymer chains before chopping is thus negligibly small compared to thenumber of moles Z of the Z(OH)₂ added in the second step. If the DP ofthe polymer prepared in the first step is not high, the number of molesof the polymer chains before chopping is not negligible compared to thenumber of moles Z of the chopping agent Z(OH)₂ added in the second step.The number of moles of the chains of the final macropolyol is the sum ofthe number of moles (i.e. N/n) of the chains of the polymer in the firststep before chopping and the number of moles of the Z(OH)₂ added in thesecond step. This leads to an increase in the number x₀ of the chainshaving none of the Z(O—)_(a) units in the final macropolyol by thenumber of moles of the chains of the polymer before chopping. Generally,macrodiol chains having none of the Z(O—)_(a) units are highlycrystalline, which renders the final product waxy or causescrystallization of the final product in an oil, making the final productsuspended. Macropolyols in the form of waxes or suspended oils are notsuitable for use as polyurethane raw materials, coating agents orlubricating agents. Another disadvantage is that the linear polymerchains cannot participate in cross-linking.

The present invention features in that since the polymer prepared in thefirst step before chopping has a sufficiently high molecular weight, thenumber of moles (that is, N/n in FIGS. 2 and 3) of the chains in thepolymer is negligible (<10%) compared to the number of moles (that is, Zin FIGS. 2 and 3) of the chopping agent added in the second step. Inthis special situation, the following equations are derived:

1) the DP of a macropolyol produced by chopping a polymer having aninfinite DP, a=(Z+N)/Z

2) the DP of a macropolyol produced by chopping a polymer having a DP ofn, a′=(Z+N)/(Z+N/n)

3) when the number of moles N/n of polymer chains is one tenth of thenumber of moles Z of a chopping agent, that is, N/n=(1/10)Z,a′=(Z+N)/(Z+N/n)=(Z+N)/(Z+0.1Z)=(10/11)a

4) when the number of moles N/n of polymer chains is one tenth of thenumber of moles Z of a chopping agent, that is, N/n=(1/10)Z, therelations n=10(N/Z)=10(a−1)=10[(10/11)a′−1] are satisfied based on theequations 1) to 3).

The DP (i.e. a′) of the macropolyol of interest is between 5 and 20 (seebelow). In the above equation, when a′ is 5, n is 35. That is, the DP ofthe polymer before chopping is 7 times greater than that of the finalmacropolyol after chopping. When a′ is 20, n is 171. That is, the DP ofthe polymer before chopping is about 8.5 times greater than that of thefinal macropolyol after chopping. In other words, when the DP of thepolymer before chopping is at least 7 times greater than that of thefinal macropolyol after chopping, the number of moles (i.e. N/n in FIGS.2 and 3) of the chains of the polymer prepared in the first step beforechopping is negligible (<10%) compared to the number of moles (i.e. Z inFIGS. 2 and 3) of the chopping agent added in the second step. Assumingthat the molecular weight of the chopping agent is roughly the same asthat of the repeating unit of the polymer before chopping, the aboverelations are sufficiently satisfied when the molecular weight of thepolymer before chopping is about 10-fold higher than that of themacropolyol after chopping. Referring to Tables 1-3 in the Examplessection that follows, the molecular weights of the polymers beforechopping were 10-fold higher than those of the macropolyols.

It is more desirable that the number of moles of the chains of thepolymer before chopping is less than 5% with respect to the number ofmoles of the chopping agent. That is, when N/n=(1/20)Z, the relationsn=20(N/Z)=20(a−1)=10[(20/21)a′−1] are satisfied based on the aboveequations. When a′ is 5, n is 75, which means that the DP of the polymerbefore chopping is 15 times greater than that of the final macropolyolafter chopping. When a′ is 20, n is 360, which means that the DP of thepolymer before chopping is 18 times greater than that of the finalmacropolyol after chopping. Assuming that the molecular weight of thechopping agent is roughly the same as that of the repeating unit of thepolymer before chopping, it is sufficient that the molecular weight ofthe polymer before chopping is about 20-fold or more higher than that ofthe final macropolyol after chopping. In the Examples section thatfollows, most of the polymers before chopping had at least 20-foldhigher molecular weights than the macropolyols.

The ends of the final macropolyol produced by chopping thehigh-molecular-weight polymer with the Z(OH)_(a) are mostly capped with—OH. This chopping is the feature of the present invention. If themolecular weight of the polymer before chopping is not sufficientlyhigh, the number of moles of the end-capping groups included in thepolymer is not negligible compared to that of —OH in the Z(OH)_(a), andas a result, a considerable number of the end-capping groups included inthe polymer remain in the final macropolyol. In the first step, thecondensation reaction of DMC with HOAOH as a diol affords an aliphaticpolycarbonate end-capped with —OH and —C(O)OCH₃. In a state in whichterminal —OH groups are present in an excessive amount, the condensationreaction is carried out while removing mostly the diol. However, thereaction rate is very slow and the yield is also low, making itdifficult to obtain a high molecular weight of the polymer (see (a) ofFIG. 1). Based on this condensation reaction, a method for directlyproducing a macropolyol was reported (EP0302712B1). According to thismethod, a large amount (1 mol %) of Na as a catalyst is added to promotethe condensation reaction. Due to the considerable amount of thecatalyst, the reaction product should be dissolved in methylene chlorideand neutralized by washing with a dilute aqueous acid solution. Manyattempts have been made to prepare high-molecular-weight polymersend-capped with excess —C(O)OCH₃ groups while removing DMC. However,after the molecular weights of the polymers increase to some extent, thereaction rates are greatly slowed down, leading to a limited increase inthe molecular weight of the polymers. Based on this method, Sivaram etal. reported the preparation of polymers having weight average molecularweights of 6,000 to 8,000 by condensation of DMC with various diols(e.g., 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and1,4-bis(hydroxymethyl)cyclohexane) using1,3-diphenoxytetra-n-butyldistannoxane as a catalyst (Polymer Vol. 36,4851-4854, 1995). U.S. Pat. No. 5,171,830 discloses a process for thepreparation of aliphatic polycarbonates whose molecular weights are onthe order of 2,400 by condensing DMC with various diols using a tertiaryamine or alkylammonium salt as a catalyst. According to a recent report,an attempt has been made to synthesize aliphatic polycarbonates bycondensation of various diols and DMC using1-n-butyl-3-methylimidazolium-2-carboxylate (1 mol %) as a catalyst(Polym. Chem., 2012, 3, 1475). However, the aliphatic polycarbonateshave number average molecular weights not higher than 6,700. ChunchengLi et al. reported the preparation of an aliphatic polycarbonate with anumber average molecular weight of several tens of thousands bycondensation of DMC and 1,4-butanediol using aTiO₂/SiO₂/poly(vinylpyrrolidone) mixture as a solid catalyst (Polym Int2011; 60: 1060-1067; Journal of Macromolecular Science, Part A: Pure andApplied Chemistry (2011) 48, 583-594). These reported methods allrequire the removal of the catalysts by washing after the preparation ofthe polymers. Since the polymers prepared by the methods have terminal—C(O)OCH₃ groups in common, chopping of the polymers whose molecularweights are not considerably high leads to the production ofmacropolyols including a considerable number of terminal —C(O)OCH₃groups, which are not suitable for use as polyurethane raw materials. Incontrast, the method of the present invention features in that a polymerwith a very high molecular weight is prepared from a diol and DMC inwhich —OH and —OCH₃ are present in a ratio of ˜1:1, while removingmostly methanol and is then chopped into a macropolyol ((b) of FIG. 1).By chopping the high-molecular-weight polymer, the number of moles ofthe end-capping groups in the polymer before chopping can be greatlyreduced to a negligible level, leading to the production of themacropolyol whose terminal groups are mostly —OH groups.

After complete dehydration of the diol monomer, oligomers are preparedin which —OH and —OCH₃ are present in a ratio of ˜1:1, and are thensubjected to condensation. This can considerably enhance the reactionrate. Thus, the high-molecular-weight aliphatic polycarbonate can beprepared in a short time even in the presence of a small amount of abase catalyst ((b) of FIG. 1). The condensation catalyst can be used forthe subsequent chopping reaction without the need to be removed. Thebase catalyst may include a lithium, sodium, or potassium cation and maybe used in an amount of 0.01 to 0.1 mol %, preferably 0.02 to 0.05 mol%, based on the HOAOH. The presence of an excess of the catalyst mayhave an adverse effect on the growth of molecular weight. As thereaction proceeds, the catalyst may be precipitated and may affect thephysical properties of the final macrodiol and polyol. Meanwhile, thepresence of the catalyst in an amount of less than 0.01 mol % does notcontribute to an increase in reaction rate, making it difficult toprepare the high-molecular-weight polymer. Since HO-A-OH added aftercompletion of the condensation is mostly incorporated into the polymerchains, there is no significant change between the molar ratio of theHOAOH to the catalyst initially added and the molar ratio of the —OAO—units to the catalyst in the final macropolyol.

The use of a small amount of the catalyst also avoids the need to removethe catalyst remaining after completion of the reaction. The initiallyadded catalyst present in the final macropolyol is a salt composed of analkali metal cation and an alkoxy anion of the end-capping group.Although the base catalyst remains unremoved or unneutralized, it doesnot change the final macropolyol at room temperature and can thus beutilized for polyurethane production without the need to be removed. Asa result of reacting with dibutyltin dichloride or a tertiary aminehydrochloride salt, the catalyst may be converted to a dibutyltincompound or a tertiary amine, which is a typical catalyst forpolyurethane production. The total amount of the base catalyst initiallyadded may also be used for urethane production. Alternatively, a portionof the base catalyst may be neutralized and the remaining portionthereof may be utilized as a catalyst for polyurethane production. Thebase catalyst may be neutralized with melamine phenylphosphonate or anacyl halide.

Like the conventional method shown in (a) of FIG. 1, methods fordirectly producing aliphatic polycarbonate macropolyols are known in EP302712, EP 2,036,937, and EP 798,328. However, the known methods are notsuitable for the production of macropolyols by choppinghigh-molecular-weight polymers in which the number of moles of terminal—OH groups is from aZ to aZ+0.2Z (where Z represents the number of molesof Z(O—)_(a) as a repeating unit), which is claimed in the presentinvention. According to the conventional method, the condensationreaction is carried out while removing by-produced methanol during theproduction of a macropolyol. However, DMC participating in thecondensation reaction is distilled off together with methanol, making itdifficult to control the molecular weight of the final product dependingon the composition of the reactants initially added. In the case where amacropolyol is produced by condensation of HOAOH and Z(OH)_(a) with DMCin accordance with the conventional method, the initial number of molesof —OH groups corresponds to the sum of the product of the number ofmoles Z of the Z(OH)_(a) and a and the product of the number of moles ofHOAOH and 2. As the condensation reaction proceeds, the number of molesof —OH decreases and approximates aZ. When the condensation reaction isallowed to proceed further, the number of moles of —OH decreases tobelow aZ. At this time, many branched polymer chains begin to cross-linkwith each other, resulting in a dramatic increase in molecular weight,and the condensation product is finally gelled. When the number of theterminal —OH groups reaches aZ to aZ+0.2Z, more preferably aZ+0.1Z,during the series of consecutive condensations, it is practicallydifficult to quench the reaction (see Comparative Example 1). Thedistributions of the chains of macropolyols produced by chopping throughtransesterification, which is the feature of the present invention, canbe accurately predicted by statistical analysis (FIGS. 2 and 3), whereasthe distributions of the chains of macropolyols directly produced bycondensation are not easy to predict by statistical analysis.

Similarly to the method of the present invention, U.S. Pat. No.5,143,997 issued on Sep. 1, 1992 discloses a method for producing apolycarbonate-polyol by transesterification of a polycarbonate-diol withtrimethylolpropane as a triol compound or pentaerythritol as a tetraolcompound. Before chopping, the macrodiol has a number average molecularweight as low as 2000 and is end-capped with —OH. That is, the macrodiolis produced by the method shown in (a) of FIG. 1 and is chopped into amacropolyol having a lower molecular weight ≤1000, which is suitable foruse as a polyurethane raw material. Specifically, a poly(hexamethylenecarbonate)-polyol having a number average molecular weight of 500 to1000 is produced by transesterification of a poly(hexamethylenecarbonate)-diol having a number average molecular weight of 2000 withtrimethylol propane (CH₃C(CH₂OH)₃) or pentaerythritol (C(CH₂OH)₄) at220° C. for 8 hours in the presence of tetrabutyl titanate ((nBuO)₄Ti)as a catalyst. The polycarbonate-diol before chopping is chopped withsubstantially the same number of moles of pentaerythritol (C(CH₂OH)₄) asa chopping agent to produce a macropolyol having a molecular weight of1000. At this time, the number of moles of terminal —OH groups is 4Z+2Z(where Z represents the number of moles of pentaerythritol), which iswell outside the range (4Z+0.2Z) claimed in the present invention. Inthis case, a considerable number of polymer chains including only theunit —OAO— rather than the unit Z(O—)_(a) are present in the macropolyoland are precipitated as crystals in the final product. Thiscrystallization renders the final product waxy or suspended oily(Comparative Example 2). Transesterification of 1 mole of apolycarbonate-diol having a molecular weight of 2,000 with 4 moles ofpentaerythritol gives a macropolyol having a molecular weight of 500. Asin this case, the number of moles of terminal —OH groups is 4Z+0.5Z(where Z represents the number of moles of the pentaerythritol), whichis well outside the range (4Z+0.2Z) claimed in the present invention.The method of the present invention is distinguished from the prior artin that a high-molecular-weight polymer is chopped into a macropolyolwith a broad molecular weight distribution, the number of choppingagent-free chains in the final product is minimized, and the kind of acatalyst used is different.

Specifically, the present invention provides an aliphatic polycarbonatemacrodiol wherein the HOAOH as a raw material for the repeating unit—OAO— is selected from the group consisting of Formulae 1a to 1c:

the repeating unit Z(O—)_(a) is Z(O—)₂ (i.e. a is 2), and

the Z(OH)₂ as a raw material for the Z(O—)₂ is selected from the groupconsisting of Formulae 1d to 1h:

The diol compounds of Formulae 1a to 1h are currently prepared on acommercial scale and are in use.

More specifically, the HOAOH as a raw material for the repeating unit—OAO— is a mixture of 80 to 95 mol % of 1,4-butanediol represented byFormula 1a and 5 to 20 mol % of the diol compound represented by Formula1b or 1c, and the Z(O—)₂ repeating units are present in an amount of 5to 20 mol % with respect to the —OAO— repeating units. The use of1,4-butanediol as the diol compound enables the production of themacropolyol in a highly economical manner due to its low price.1,4-Butanediol is an important compound necessary for the production ofbiodegradable polymers. Additional factories for commercial productionof 1,4-butanediol from coal have recently been built. Processes forproducing 1,4-butanediol by biomass fermentation are currently underactive development. However, the use of aliphatic polycarbonate-polyolsbased on 1,4-butanediol is still insufficient becausepolycarbonate-diols produced using 1,4-butanediol as a major componentare highly crystalline, which renders the final products waxy. When amacropolyol is produced by the conventional condensation process shownin (a) of FIG. 1, methanol as a byproduct needs to be removed. However,it is difficult to selectively remove methanol due to the low boilingpoint and high polarity of 1,4-butanediol. Therefore, the condensationprocess shown in (a) of FIG. 1 is not suitable for the production of amacropolyol. For these reasons, the development of macropolyols using1,4-butanediol as a major component is still unsatisfactory despite thelow price of 1,4-butanediol. 1,6-Hexanediol is currently in use as amajor raw material for aliphatic polycarbonate-diols but is expensivecompared to 1,4-butanediol.

The molecular weight (i.e. DP) of the macropolyol produced by the methodof the present invention varies depending on the amount of the choppingagent added. When the Z(O—)₂ repeating units are present in an amount of5 mol % with respect to the —OAO— repeating units, the DP of the finalmacrodiol or macropolyol is 21 (=105/5). Meanwhile, when the Z(O—)₂repeating units are present in an amount of 20 mol % with respect to the—OAO— repeating units, the DP of the final macrodiol or macropolyol is 6(=120/20). Within this range, the final product is suitable for use as apolyurethane raw material, a coating material, a lubricating agent, etc.

An aliphatic polycarbonate-diol obtained by condensation of one of1,6-hexanediol, 1,5-pentanediol and 1,4-butanediol with DMC is in theform of a crystalline solid. For this reason, the aliphaticpolycarbonate-diol is undesirable as a polyurethane raw material(Journal of Applied Polymer Science, Vol. 111, 217-227 (2009)). Viscousmacrodiols are commonly used as raw materials for polyurethaneproduction. The raw materials are commonly obtained by condensing amixture of two or more diols with DMC (EP 302712; US 2010/0292497 A1).In Examples 5, 6, 8, and 9 that follow, inexpensive 1,4-butanediol as amajor component and 5 to 20 mol % of another diol were used to preparehigh-molecular-weight aliphatic polycarbonates, which were then choppedwith another diol Z(OH)₂ as a chopping agent to produce macrodiols inwhich three repeating units are present. The use of the diols increasesthe possibility that the final products may be viscous.

The present invention also provides a branched aliphatic polycarbonatemacropolyol in which the HOAOH as a raw material for the repeating unit—OAO— is selected from the group consisting of Formulae 1a to 1h and theZ(OH)_(a) as a raw material for the repeating unit Z(O—)_(a) is selectedfrom the group consisting of Formulae 2a to 2d:

The branched macropolyol is cross-linkable during urethane productionand can thus be used as an important raw material for a hard foam or acoating agent.

For the above-described reasons, aliphatic polycarbonate macropolyolsare commercially attractive in which the HOAOH as a raw material for therepeating unit —OAO— is a mixture of 80 to 95 mol % of 1,4-butanedioland 5 to 20 mol % of the diol selected from the group consisting ofFormulae 1b to 1h and the Z(O—)_(a) repeating units are present in anamount of 5 to 20 mol % with respect to the —OAO— repeating units.

The chopping agent Z(OH)_(a) of Formula 2a is the most commercially usedcompound. Chopping with this compound facilitates the production ofviscous materials (Examples 22-35).

Another aspect of the present invention provides an aliphaticpolycarbonate-co-aromatic polyester macropolyol including —OAO— andZ(O—)_(a) as repeating units in which the repeating units —OAO— andZ(O—)_(a) are linked via carbonyl (—C(O)—) and —C(O)YC(O)— as linkers orare bonded to hydrogen to form terminal —OH groups wherein A is asubstituted or unsubstituted C₃-C₆₀ alkylene or a combination of two ormore substituted or unsubstituted C₃-C₆₀ alkylenes, a is an integer from2 to 4, provided that when a is 2, Z is a substituted or unsubstitutedC₃-C₆₀ alkanediyl, when a is 3, Z is a substituted or unsubstitutedC₃-C₆₀ alkanetriyl, and when a is 4, Z is a substituted or unsubstitutedC₄-C₆₀ alkanetetriyl, and Y is a substituted or unsubstituted C₅-C₂₀arylene, a combination of two or more substituted or unsubstitutedC₅-C₂₀ arylenes, a substituted or unsubstituted C₅-C₂₀ heteroarylene ora combination of two or more substituted or unsubstituted C₅-C₂₀heteroarylenes.

There are no reports on aliphatic polycarbonate-aromatic polyestercopolymers in which —OAO— repeating units are randomly linked viacarbonyl (—C(O)—) and —C(O)YC(O)—. The macropolyol of the presentinvention is produced by preparing a high-molecular-weight aliphaticpolycarbonate in a manner similar to the conventional method, adding anaromatic diester to the aliphatic polycarbonate to prepare a randomcopolymer of the aliphatic polycarbonate and the aromatic polyester, andchopping the random copolymer with Z(OH)_(a). The aliphaticpolycarbonate-aromatic polyester macropolyol is a structurally newcompound having the chain distributions analyzed in FIGS. 2 and 3.

The aliphatic polycarbonate-co-aromatic polyester macrodiol in which theHOAOH as a raw material for the repeating unit —OAO— is 1,4-butanediol,a in the repeating unit Z(O—)_(a) is 2, the Z(OH)₂ as a raw material forthe repeating unit Z(O—)₂ is selected from the group consisting ofFormulae 1a to 1h, and the HOC(O)YC(O)OH as a raw material for thelinker —C(O)YC(O)— is selected from phthalic acid, isophthalic acid, andterephthalic acid is commercially economical, taking into considerationthe prices of the raw materials.

When the —C(O)YC(O)— linkers are present in an amount of 5 to 50 mol %,based on the —OAO— repeating units, the macropolyol is easy tosynthesize. Meanwhile, when the Z(O—)₂ repeating units are present in anamount of 5 to 20 mol %, based on the —OAO— repeating units, the DP ofthe macropolyol is preferably in the range suitable for use inpolyurethane, coatings, and lubricating agents.

The linker HOC(O)YC(O)OH as a raw material for the linker —C(O)YC(O)— ispreferably isophthalic acid or terephthalic acid because a viscous formof the final product is easily obtained (Examples 37-39).

The macropolyol can be branched when the Z(OH)_(a) as a raw material forthe repeating unit Z(O—)_(a) is selected from the group consisting ofFormulae 2a to 2d. The branched macropolyol is suitable for use as across-linkable polyurethane raw material.

The present invention also provides a method for producing the aliphaticpolycarbonate macropolyol. Specifically, the method of the presentinvention includes condensing HOAOH with DMC in the presence of a basecatalyst while removing methanol to prepare an aliphatic polycarbonatewith a number average molecular weight of 10000 or higher (first step)and transesterifying the condensation product with Z(OH)_(a) (secondstep). In this connection, U.S. Pat. Nos. 5,143,997 and 8,344,092describe methods in which an aliphatic polycarbonate-diol having a lowmolecular weight (Mn) of 2000 is chopped into a macropolyol having alower molecular weight (Mn<1000) by transesterification with a triol ortetraol compound. These methods use tetraalkoxytitanium compounds astransesterification catalysts.

The method of the present invention is distinguished from the knownmethods in that the base catalyst used is simple. The method of thepresent invention has an advantage in that the catalyst used for thepreparation of the high-molecular-weight aliphatic polycarbonate in thefirst step is used without the need to be removed instead of adding anew base catalyst. The method of the present invention is alsodistinguished from the known methods in that the aliphatic polycarbonatehaving a molecular weight of 10,000 or higher is subjected to atransesterification reaction. No particular restriction is imposed onthe upper limit of the number average molecular weight of the aliphaticpolycarbonate. For example, the aliphatic polycarbonate may have anumber average molecular weight of 10000 to 200000, preferably 10000 to100000.

The base catalyst is composed of a lithium, sodium or potassium cationand an alkoxy anion formed by deprotonation of the HO-A-OH. The basecatalyst is used in an amount ranging from 0.01 mol % to 0.1 mol %,based on the HO-A-OH. The use of the base catalyst in the range definedabove is economically desirable and is suitable for the preparation ofthe high-molecular-weight polymer in the first step.

The present invention also provides a method for producing an aliphaticpolycarbonate-co-aromatic polyester macropolyol, including condensingHOAOH, DMC, and MeOC(O)YC(O)OMe in the presence of a base catalyst whileremoving methanol to prepare an aliphatic polycarbonate-co-aromaticpolyester with a number average molecular weight of 10000 or higher(first step) and transesterifying the condensation product withZ(OH)_(a) (second step).

Effects of the Invention

According to the methods of the present invention, an aliphaticpolycarbonate or an aliphatic polycarbonate-co-aromatic polyester havinga molecular weight of 10000 or higher is prepared and thehigh-molecular-weight polymer or copolymer is chain-chopped bytransesterification with various alcohol compounds (Z(OH)_(a)) aschopping agents to produce macropolyols with lower molecular weights.The macropolyols have precisely controllable molecular weights andpredictably unique polymer chain distributions. The macropolyols of thepresent invention feature in that the number of moles of terminal —OHgroups is uniquely in the range of aZ to aZ+0.2Z (where Z represents thenumber of moles of the chopping agent Z(OH)_(a). The chopping allows themacropolyols to have various structures and compositions, increasing thepossibility that the macropolyols may be utilized as polyurethane rawmaterials, coating materials, lubricating agents, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 compares (a) a traditional method for producing an aliphaticpolycarbonate macrodiol with (b) a method for producing an aliphaticpolycarbonate macrodiol according to the present invention.

FIG. 2 shows the statistical distribution of chains of a macrodiolobtained using a diol as a chopping agent.

FIG. 3 shows the statistical distribution of chains of a macrodiolobtained using a triol as a chopping agent.

BEST MODE FOR CARRYING OUT THE INVENTION

The effects of the present invention will be explained in detail withreference to the following examples, including comparative examples.However, these examples are provided for illustrative purposes only andare not intended to limit the scope of the invention. Sodium was reactedwith and dissolved in 1,4-butanediol, and then phthaloyl chloride wasadded thereto. The phthaloyl chloride was used in an amount of 0.25equivalents per equivalent of the sodium. After stirring at 80° C.overnight, the mixture was distilled under a vacuum of 0.15 mmHg at 120°C. to obtain anhydrous 1,4-butanediol.

Examples 1-9: Condensation of Formula 1a (and Optionally Formula 1b or1c) With DMC and Subsequent Chopping of the Condensation Product WithOne of Formulae 1b to 1h

First step: 1,4-Butanediol (Formula 1a) and optionally 1,5-pentanediol(Formula 1b) or 1,6-hexanediol (Formula 1c) were placed in a 3-neckflask such that the total number of moles was 111 mmol. The1,5-pentanediol or 1,6-hexanediol was used in the amount of 0 or 10 mol%, as shown in Table 1. NaH (0.056 mmol, 0.05 mol %) was added to theflask to form HO(CH₂)₄O⁻Na⁺ and then 15.7 g (174 mmol) of dimethylcarbonate (DMC) was added thereto. A mechanical stirrer was connected toone neck of the flask, a manifold attached with a vacuum line and anitrogen line was connected to another neck of the flask, and adistillation unit was connected to the remaining neck of the flask.After the reaction flask was immersed in a thermostatic bath at 120° C.,the reaction was carried out for 1 h while distilling off formedmethanol and a portion of the DMC at ambient pressure. The reaction wascontinued for a total of 3.5 h while removing volatiles at an elevatedtemperature of 190° C. and a reduced pressure of 570 mmHg for 0.5 h, 380mmHg for 1 h, and 190 mmHg for 2 h. Thereafter, the reaction was allowedto proceed at 190° C. for additional 2 h while removing volatiles undera high vacuum of 0.3 mmHg, which was maintained using a vacuum pump.

Second step: A diol selected from Formulae 1b to 1h was used as achopping agent. The chopping agent was added to the condensation productobtained in the first step. The chopping agent was used in an amount of15 mol % (16.7 mmol), based on the diol(s) initially added. The reactionwas carried out for 3 h while slowly cooling to 150° C. from 190° C.Within 10 min from the beginning of the reaction, a remarkable reductionin the viscosity of the reaction mixture was observed. As a result ofthe reaction, the condensation product was chopped with the choppingagent. The experimental results are summarized in Table 1.

TABLE 1 <Experimental results obtained when condensation product ofFormula 1a (and optionally Formula 1b or 1c) and DMC was chopped withone of Formulae 1b to 1h> Chopping agent, Yield^(a) Before chopping-After chopping- T_(g) State after State after 7 HOAOH Z(OH)₂ (15 mol %)(%) M_(n) (M_(w)/M_(n))^(b) M_(n) (M_(w)/M_(n))^(b) (° C.)^(c) 1 daydays Example 1 1a 1b 81 90000 (1.71) 2400 (1.70) −12 Wax Wax Example 21a 1c 88 89000 (1.82) 2000 (1.70) −12 Wax Wax Example 3 1a 1d 88 40000(1.56) 1800 (1.57) −48 Transparent Slight oil suspension Example 4 1a 1e91 58000 (1.63) 2000 (1.56) −45 Transparent Wax oil Example 5 1a + 1b 1e90 54000 (1.56) 1900 (1.60) −48 Transparent Transparent oil (90:10) oilExample 6 1a + 1c 1e 83 66000 (1.62) 1900 (1.60) −49 TransparentTransparent oil (90:10) oil Example 7 1a + 1c 1f 89 64000 (1.78) 2000(1.62) −31 Wax Wax (90:10) Example 8 1a + 1c 1g 91 79000 (1.59) 2200(1.65) −40 Orange oil Orange oil (90:10) Example 9 1a + 1c 1h 93 77000(1.63) 2200 (1.60) −38 Transparent Transparent oil (90:10) oil ^(a)Valuecalculated from the actual mass of the obtained condensation productrelative to the theoretical maximum mass of the condensation product.^(b)Value measured on the basis of polystyrene standard in THF at 40° C.by GPC. ^(c)Glass transition temperature measured by DSC.

The results in Table 1 demonstrate the production of aliphaticpolycarbonate macrodiols and show that the molecular weights of thecondensation products were reduced to at least 1/10, more preferably1/20, by chopping, which is the feature of the present invention, andmost of the macrodiols were obtained in the form of oils (some thereofwere in the form of waxes). Particularly, the oily macrodiols werereadily obtained when the diols of Formula 1a and Formula 1b or 1c wereused in combination rather than when the diol of Formula 1a was usedalone as the HOAOH.

Examples 10-21: Condensation of Formula 1a (and Optionally Formula 1c)With DMC and Subsequent Chopping of the Condensation Product With One ofFormulae 2a to 2d

The first step of Examples 1-9 was repeated.

The second step of Examples 1-9 was repeated, except that a diolselected from Formulae 2a to 2d was used as a chopping agent. Theexperimental results are summarized in Table 2.

TABLE 2 <Experimental results obtained when condensation product ofFormula 1a (and optionally Formula 1c) and dimethyl carbonate waschopped with one of Formulae 2a to 2d> Chopping agent, Yield^(a) Beforechopping- After chopping- T_(g) State after 1 State after 7 HOAOHZ(OH)_(a) (15 mol %) (%) M_(n) (M_(w)/M_(n))^(b) M_(n) (M_(w)/M_(n))^(b)(° C.)^(c) day days Example 10 1a 2a 81 69000 (1.62) 2200 (1.81) −49 WaxWax Example 11 1a 2b 86 43200 (1.58) 2100 (1.96) −45 Wax Wax Example 121a 2c 85 49900 (1.54) 2000 (1.84) −57 Wax Wax Example 13 1a 2d 82 50000(1.61) 1300 (1.71) −41 Wax Wax Example 14 1a + 1c 2a 81 53000 (1.43)2100 (1.85) −50 Transparent Wax (95:5) oil Example 15 1a + 1c 2b 8787000 (1.63) 2200 (1.87) −48 Transparent Suspended (95:5) oil oilExample 16 1a + 1c 2c 84 50000 (1.72) 1000 (1.31) −69 Yellow oil Yellow(95:5) Oil Example 17 1a + 1c 2d 89 39000 (1.58) 2500 (1.93) −44Transparent Suspended (95:5) oil oil Example 18 1a + 1c 2a 93 65000(1.62) 2300 (1.84) −58 Transparent Transparent (90:10) oil oil Example19 1a + 1c 2b 85 50000 (1.53) 2400 (1.83) −51 Transparent Transparent(90:10) oil oil Example 20 1a + 1c 2c 82 21200 (1.59) 1800 (1.88) −62Yellow oil Yellow (90:10) oil Example 21 1a + 1c 2d 73 50200 (1.73) 1800(1.75) −48 Suspended Suspended (90:10) oil oil ^(a)Value calculated fromthe actual mass of the obtained condensation product relative to thetheoretical maximum mass of the condensation product. ^(b)Value measuredon the basis of polystyrene standard in THF at 40° C. by GPC. ^(c)Glasstransition temperature measured by DSC.

The results in Table 2 reveal that chopping of the high-molecular-weightaliphatic polycarbonates with the chopping agents of Formulae 2a to 2dled to the production of macropolyols with lower molecular weights. Thepolymers prepared in the first step before chopping were confirmed tohave molecular weights at least 10 times (mostly at least 20 times)higher than those of the macropolyols produced after chopping, which isthe feature of the present invention. The oily macropolyols were readilyobtained when the diols of Formula 1a and Formula 1c were used incombination rather than when the diol of Formula 1a was used alone asthe HOAOH.

Examples 22-35: Condensation of Formula 1a and One of Formulae 1b to 1hWith DMC and Subsequent Chopping of the Condensation Product WithFormula 2a

First step: 1,4-Butanediol (Formula 1a) and an additional diol selectedfrom Formulae 1b to 1h were placed in a 3-neck flask such that the totalnumber of moles was 111 mmol. The additional diol was used in the amountof 5 mol % or 10 mol %, as shown in Table 1. NaH (0.056 mmol, 0.05 mol%) was added to the flask to form HO(CH₂)₄O⁻Na⁺ and then 15.7 g (174mmol) of dimethyl carbonate (DMC) was added thereto. The subsequentprocedure was carried out in the same manner as in Examples 1-9.

Second step: The triol of Formula 2a as a chopping agent was added tothe condensation product obtained in the first step. The chopping agentwas used in an amount of 15 mol % (4.43 g, 16.7 mmol), based on thediols initially added. The reaction was carried out for 3 h while slowlycooling to 150° C. from 190° C. Within 10 min from the beginning of thereaction, a remarkable reduction in the viscosity of the reactionmixture was observed. As a result of the reaction, the condensationproduct was chopped with the chopping agent. The experimental resultsare summarized in Table 3.

TABLE 3 <Experimental results obtained when condensation product ofFormulae 1a, one of Formulae 1b to 1h, and dimethyl carbonate waschopped with Formula 2a> Chopping agent, Yield^(a) Before chopping-After chopping- T_(g) State after 1 State after 7 HOAOH Z(OH)_(a) (15mol %) (%) M_(n) (M_(w)/M_(n))^(b) M_(n) (M_(w)/M_(n))^(b) (° C.)^(c)day days Example 22 1a + 1b 2a 85 64000 (1.55) 2000 −44 SuspendedSuspended (95:5) (1.74) oil oil Example 23 1a + 1d 2a 85 35000 (1.72)2000 −42 Slight Slight (95:5) (1.86) suspension suspension Example 241a + 1e 2a 83 38000 (1.58) 2000 −46 Suspended Slight (95:5) (1.71) oilsuspension Example 25 1a + 1f 2a 82 48000 (1.64) 2000 −40 Slight Slight(95:5) (1.81) suspension suspension Example 26 1a + 1g 2a 83 45000(1.56) 2100 −41 Slight Slight (95:5) (1.86) suspension suspensionExample 27 1a + 1h 2a 96 43000 (1.57) 1900 −48 Transparent Transparent(95:5) (1.83) oil oil Example 28 1a + 1b 2a 85 85000 (1.45) 2000 −46Transparent Transparent (90:10) (1.79) oil oil Example 29 1a + 1d 2a 8245000 (1.61) 2200 −43 Transparent Transparent (90:10) (1.84) oil oilExample 30 1a + 1e 2a 85 51000 (1.51) 2000 −38 Transparent Transparent(90:10) (1.75) oil oil Example 31 1a + 1f 2a 91 58000 (1.61) 2100 −32Transparent Transparent (90:10) (1.82) oil oil Example 32 1a + 1g 2a 8244000 (1.56) 1900 −36 Slight Slight (90:10) (1.80) suspension suspensionExample 33 1a + 1h 2a 87 81000 (1.77) 2100 −40 Transparent Transparent(90:10) (1.94) oil oil Example 34 1a + 1b 2a 87 60000 (1.40) 4500 −46Wax Wax (90:10)  (5 mol %) (1.83) Example 35 1a + 1b 2a 85 87000 (1.50)3200 −43 Wax Wax (90:10) (10 mol %) (1.58) ^(a)Value calculated from theactual mass of the obtained condensation product relative to thetheoretical maximum mass of the condensation product. ^(b)Value measuredon the basis of polystyrene standard in THF at 40° C. by GPC. ^(c)Glasstransition temperature measured by DSC.

The results in Table 3 show that most of the macropolyols produced bychopping the high-molecular-weight aliphatic polycarbonates, which wereprepared using 1,4-butanediol as a major raw material, with Formula 2aas a chopping agent were in the form of oils. All polymers prepared inthe first step before chopping were confirmed to have molecular weightsat least 10 times (mostly at least 20 times) higher than those of themacropolyols produced after chopping.

Examples 36-39: Condensation of Formula 1a, DMC, and MeOC(O)YC(O)OMe andSubsequent Chopping of the Condensation Product With Formula 1a or 1d

First step: 1,4-Butanediol (Formula 1a, 10.0 g, 111 mmol) was placed ina 3-neck flask and then NaH (0.111 mmol, 0.1 mol %) was added thereto toform HO(CH₂)₄O⁻Na⁺. Thereafter, dimethyl carbonate (DMC) and dimethylphthalate (or dimethyl isophthalate or dimethyl terephthalate) wereadded in the amounts shown in Table 4. The DMC was added in an amountcorresponding to the number of moles calculated by subtracting thenumber of moles of the phthalate from the number of moles correspondingto 1.57 equivalents per equivalent of the 1,4-butanediol. A mechanicalstirrer was connected to one neck of the flask, a manifold attached witha vacuum line and a nitrogen line was connected to another neck of theflask, and a distillation unit was connected to the remaining neck ofthe flask. After the reaction flask was immersed in a thermostatic bathat 120° C., the reaction was carried out for 1 h while distilling offformed methanol and a portion of the DMC at ambient pressure. Thereaction was continued for a total of 3.5 h while removing volatiles atan elevated temperature of 190° C. and a reduced pressure of 570 mmHgfor 0.5 h, 380 mmHg for 1 h, and 190 mmHg for 2 h. Thereafter, thereaction was allowed to proceed further at an elevated temperature of210° C. for additional 2 h while removing volatiles under a high vacuumof 0.3 mmHg, which was maintained using a vacuum pump.

Second step: 1,4-Butanediol (Formula 1a) as a chopping agent was addedto the condensation product obtained in the first step. The choppingagent was used in an amount of 15 mol % (1.50 g, 16.7 mmol), based onthe diol initially added. The reaction was carried out for 3 h whileslowly cooling to 150° C. from 210° C. Within 10 min from the beginningof the reaction, a remarkable reduction in the viscosity of the reactionmixture was observed. As a result of the reaction, the condensationproduct was chopped with the chopping agent. The experimental resultsare summarized in Table 4.

TABLE 4 <Experimental results obtained when condensation product ofFormula 1a, DMC, and MeOC(O)YC(O)OMe was chopped with with Formula 1a or1d (15 mol %)> —C(O)YC(O)— Chopping Yield Before chopping- Afterchopping- T_(g) State after 1 State after 7 (mol % per 1a) agent, Z(OH)₂(%)^(a) M_(n) (M_(w)/M_(n))^(b) M_(n) (M_(w)/M_(n))^(b) (° C.)^(c) daydays Example 36 Terephthalate 1a 89 80900 2700 −42 Wax Wax (30 mol %)(1.57) (1.62) Example 37 Isophthalate 1a 89 69700 2500 −36 SlightlySuspended (30 mol %) (1.50) (1.60) suspended oil oil Example 38Phthalate 1a 91 58600 2300 −43 Slightly Slightly (30 mol %) (1.52) (2.1)suspended oil suspended oil Example 39 Phthalate 1d 89 83600 3300 −27Slightly Slightly (30 mol %) (1.57) (1.70) suspended oil suspended oil^(a)Value calculated from the actual mass of the obtained condensationproduct relative to the theoretical maximum mass of the condensationproduct. ^(b)Value measured on the basis of polystyrene standard in THFat 40° C. by GPC. ^(c)Glass transition temperature measured by DSC.

The results in Table 4 show that aliphatic polycarbonate-co-aromaticpolyester macrodiols having new structures according to claims 8-10 werereadily produced by chopping, which is the feature of the presentinvention. Particularly, the presence of the isophthalate or phthalaterepeating units was confirmed to increase the possibility that themacrodiols might be produced in the form of oils.

Examples 40-60: Condensation of Formula 1a, DMC and MeOC(O)YC(O)OMe andSubsequent Chopping of the Condensation Product With One of Formulae 2ato 2d

The first step of Examples 36-39 was repeated, except that the amount ofdimethyl phthalate (or dimethyl isophthalate or dimethyl terephthalate)added was adjusted to the range of 10 to 50 mol %. When the phthalatewas used in an amount not larger than 20 mol %, volatiles were finallyremoved under a high vacuum of 0.3 mmHg at 190° C. instead of at 210° C.

The second step of Examples 36-39 was repeated, except that a diolselected from Formulae 2a to 2d was used as a chopping agent. Theexperimental results are summarized in Table 5.

TABLE 5 <Experimental results obtained when condensation product ofFormula 1a, DMC, and MeOC(O)YC(O)OMe was chopped with one of Formulae 2ato 2d (15 mol %)> —C(O)YC(O)— Chopping Yield Before chopping- Afterchopping- T_(g) State after 1 State after 7 (mol % per 1a) agent,Z(OH)_(a) (%)^(a) M_(n) (M_(w)/M_(n))^(b) M_(n) (M_(w)/M_(n))^(b) (°C.)^(c) day days Example 40 Isophthalate 2a 88 72000 2400 −43Transparent Transparent (10 mol %) (1.42) (1.83) oil oil Example 41Isophthalate 2a 87 78000 2600 −38 Transparent Transparent (20 mol %)(1.56) (1.85) oil oil Example 42 Isophthalate 2a 87 68000 2600 −35Transparent Transparent (30 mol %) (1.50) (1.82) oil oil Example 43Isophthalate 2a 90 82600 2400 −29 Slight Suspended (40 mol %) (1.58)(1.95) suspension Oil Example 44 Isophthalate 2a 91 75200 2700 −28 WaxWax (50 mol %) (1.56) (1.83) Example 45 Isophthalate 2b 89 107200 2300−28 Transparent Transparent (30 mol %) (1.47) (1.73) oil oil Example 46Isophthalate 2c 86 80900 1900 −44 Brown oil Brown oil (30 mol %) (1.50)(1.65) Example 47 Isophthalate 2d 88 94400 2400 −24 TransparentTransparent (30 mol %) (1.39) (1.84) oil oil Example 48 Terephthalate 2a90 72900 2400 −44 Suspended Suspended (10 mol %) (1.38) (1.83) oil oilExample 49 Terephthalate 2a 89 73500 2600 −39 Wax Wax (20 mol %) (1.39)(1.88) Example 50 Terephthalate 2a 91 118100 2800 −35 Wax Wax (30 mol %)(1.41) (1.97) Example 51 Terephthalate 2a 85 80800 2800 −33 Wax Wax (40mol %) (1.49) (1.91) Example 52 Terephthalate 2a 87 78600 2900 −33 WaxWax (50 mol %) (1.44) (1.87) Example 53 Terephthalate 2b 90 81700 3000−28 Wax Wax (30 mol %) (1.53) (2.10) Example 54 Terephthalate 2c 89102700 1800 −49 Brown wax Brown wax (30 mol %) (1.63) (1.70) Example 55Terephthalate 2d 90 82500 2100 −25 Wax Wax (30 mol %) (1.44) (1.63)Example 56 Phthalate 2a 87 83000 2200 −41 Transparent Transparent (10mol %) (1.61) (1.74) oil oil Example 57 Phthalate 2a 87 47800 2300 −36Transparent Transparent (20 mol %) (1.60) (1.71) oil oil Example 58Phthalate 2a 89 62300 2500 −27 Transparent Transparent (30 mol %) (1.49)(1.62) oil oil Example 59 Phthalate 2b 85 71100 2400 −29 TransparentTransparent (30 mol %) (1.56) (1.74) oil oil Example 60 Phthalate 2d 8876400 1900 −24 Transparent Transparent (30 mol %) (1.63) (1.51) oil oil^(a)Value calculated from the actual mass of the obtained condensationproduct relative to the theoretical maximum mass of the condensationproduct. ^(b)Value measured on the basis of polystyrene standard in THFat 40° C. by GPC. ^(c)Glass transition temperature measured by DSC.

The results in Table 5 show the production of aliphaticpolycarbonate-co-aromatic polyester macrodiols with variouscompositions. Particularly, the presence of the isophthalate orphthalate repeating unit was confirmed to increase the possibility thatthe macrodiols might be produced in the form of oils.

Comparative Example 1: Attempt to Directly Produce Low-Molecular-WeightDiol by Condensation of Formula 1a With DMC

1,4-Butanediol (Formula 1a, 10.0 g, 111 mmol) and NaH (0.222 mmol, 0.2mol %) were placed in a 3-neck flask to form HO(CH₂)₄O⁻Na⁺. Thereafter,15.3 g (170 mmol) of dimethyl carbonate (DMC) was further added. The DMCwas used in a small amount compared to the amounts used in the previousexamples to synthesize oligomers whose molecular weights are on theorder of several thousands and whose ends are all capped with —OH. Amechanical stirrer was connected to one neck of the flask, a manifoldattached with a vacuum line and a nitrogen line was connected to anotherneck of the flask, and a distillation unit was connected to theremaining neck of the flask. After the reaction flask was immersed in athermostatic bath at 120° C., the reaction was carried out for 1 h whiledistilling off formed methanol and a portion of the DMC at ambientpressure. The reaction was carried out at ambient pressure and anelevated temperature of 180° C. for another 1 h until the amount ofdistilled volatiles (methanol or DMC) reached a negligible level. Aftera 1 h reaction under a reduced pressure of 380 mmHg, the reactionmixture was sampled for ¹H NMR analysis. As a result, the integralvalues corresponding to —CH₂OC(O)—, —OCH₃, and —OH were 10.1, 0.71, and1.0, respectively. After the reaction was continued at the same pressurefor additional 1 h, the integral values were changed to 11.5, 0.63, and1.0, respectively. These results indicate that the reaction rate wasvery low. For more effective removal of byproducts, the reaction wasallowed to proceed further under a high vacuum of 0.3 mmHg for 2 h. ¹HNMR analysis revealed that the peaks corresponding to —OCH₃ groupsdisappeared completely and the final polymer was end-capped with —OHonly. The polymer had a molecular weight (M_(n)) of 20000, which washigher than that expected. During the reaction under a reduced pressureof 380 mmHg, the ambient —OH groups were hydrogen-bonded with the alkoxyanions to weaken the nucleophilic attack of the alkoxy anions and werealso hydrogen-bonded with the formed methanol to impede effectiveremoval of the methanol. This hydrogen bonding is interpreted to beresponsible for the low rate of the reaction. When the pressure wasfurther reduced to 0.3 mmHg, the butanediol, DMC, and HO(CH₂)₄OC(O)OCH₃as well as methanol were removed, and as a result, the chains wereconnected to each other, leading to a rapid increase in molecularweight. Therefore, the molecular weight of the polymer was confirmed tobe difficult to control.

Comparative Example 2: Chopping of Low-Molecular-Weight CondensationProduct With Formula 2a

10 mol % of 1,4-butanediol (Formula 1a) and the diol of Formula 1e wereplaced in a 3-neck flask such that the total number of moles was 111mmol. NaH (0.056 mmol, 0.05 mol %) was added to the flask to formHO(CH₂)₄O⁻Na⁺ and then 14.5 g (161 mmol) of dimethyl carbonate (DMC) wasadded thereto. The subsequent procedure was carried out in the samemanner as in Examples 22-35. In the first step, a polymer with a numberaverage molecular weight of 5000 was obtained. Chopping of the polymerafforded a macropolyol with a number average molecular weight of 1900.The molecular weight of the polymer before chopping was on the order ofabout 2.5-fold higher than that of the macropolyol after chopping. Thepresence of a relatively large number of highly crystalline linearchains free of Z(O—)₃ in the macropolyol made the macropolyol waxy. Theshape of the macropolyol was compared with that of a macropolyol havinga number average molecular weight (Mn) at the same level. For example,the macropolyol of Example 30 (Mn=2000), which was produced by choppingthe high-molecular-weight polymer (Mn=51000) prepared using the samecomposition in the first step with the same chopping agent (Formula 2a),was in the form of a transparent oil suitable for use in polyurethaneand lubricating agents.

The invention claimed is:
 1. A method for producing an aliphaticpolycarbonate macropolyol, comprising: (a) condensing HOAOH in thepresence of a base catalyst and an agent comprising DMC to prepare acondensation product, wherein the condensation product is an aliphaticpolycarbonate with a number average molecular weight of 10000 or higher,the condensing step comprising: (a1) reacting the HOAOH with the agentat ambient pressure at a first temperature to form oligomers, wherein,in the oligomers, —OH and —OCH₃ are present in a ratio of about 1:1, and(a2) forming the condensation product from the oligomers at an elevatedtemperature higher than the first temperature and at a reduced pressurelower than ambient pressure; and (b) transesterifying the condensationproduct with Z(OH)a to form a final product, wherein the final productis an aliphatic polycarbonate with a number average molecular weightlower than that of the condensation product, wherein A is a substitutedor unsubstituted C₃-C₆₀ alkylene or a combination of two or moresubstituted or unsubstituted C₃-C₆₀ alkylenes, wherein a is an integerfrom 2 to 4, provided that, when a is 2, Z is a substituted orunsubstituted C₃-C₆₀ alkanediyl, when a is 3, Z is a substituted orunsubstituted C₃-C₆₀ alkanetriyl, and when a is 4, Z is a substituted orunsubstituted C₄-C₆₀ alkanetetriyl, wherein the aliphatic polycarbonatemacropolyol comprises: —OAO— and Z(O—)_(a) as repeating units and alinker, the linker comprising carbonyl (—C(O)—), wherein the repeatingunits —OAO— and Z(O—)_(a) are linked to each other via the linker or arebonded to hydrogen to form terminal —OH groups, wherein thetransesterifying step occurs in the presence of the base catalyst usedin the condensing step, and wherein the number average molecular weightof the condensation product is at least 10 times higher than that of thefinal product.
 2. The method according to claim 1, wherein the basecatalyst is composed of a lithium, a sodium or potassium cation, and analkoxy anion formed by deprotonation of the HOAOH, and wherein the basecatalyst is used in an amount of 0.01 mol % to 0.1 mol %, based on theHOAOH.
 3. The method according to claim 1, wherein the agent furthercomprises MeOC(O)YC(O)OMe, wherein Y is a substituted or unsubstitutedC₅-C₂₀ arylene, a combination of two or more substituted orunsubstituted C₅-C₂₀ arylenes, a substituted or unsubstituted C₅-C₂₀heteroarylene or a combination of two or more substituted orunsubstituted C₅-C₂₀ heteroarylenes.
 4. The method according to claim 3,wherein the linker further comprises —C(O)YC(O)—.
 5. The methodaccording to claim 1, wherein the step (a2) further comprising removingof methanol.
 6. The method according to claim 1, wherein the unitZ(O—)_(a) is present in an amount of 5 to 20 mol % with respect to theunit —OAO—.
 7. The method according to claim 1, wherein, in the step(a), the HOAOH is a mixture of two or more different diol compoundscontaining the substituted or unsubstituted C₃-C₆₀ alkylenes.
 8. Themethod according to claim 1, wherein, in the transesterifying step, theZ(OH)_(a) is provided in an amount of 5 to 20 mol % of the HOAOH.
 9. Themethod according to claim 1, wherein the number average molecular weightof the condensation product is higher than 50000.